English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  Facile Synthesis of Gd-DO3A-EA Conjugated with DTPA: A Novel Calcium Dependent MR Contrast Agent

Mishra, A., Pfeuffer, J., Albert, K., Mishra, A., & Logothetis, N. (2005). Facile Synthesis of Gd-DO3A-EA Conjugated with DTPA: A Novel Calcium Dependent MR Contrast Agent. Poster presented at 4th Annual Meeting of the Society for Molecular Imaging (SMI 2005), Köln, Germany.

Item is

Files

show Files
hide Files
:
pdf3498.pdf (Abstract), 30KB
Name:
pdf3498.pdf
Description:
-
OA-Status:
Visibility:
Public
MIME-Type / Checksum:
application/pdf / [MD5]
Technical Metadata:
Copyright Date:
-
Copyright Info:
-
License:
-

Locators

show
hide
Description:
-
OA-Status:

Creators

show
hide
 Creators:
Mishra, A1, 2, Author           
Pfeuffer, J1, 2, Author           
Albert, K, Author
Mishra, AK, Author           
Logothetis, NK1, 2, Author           
Affiliations:
1Department Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Max Planck Society, ou_1497798              
2Max Planck Institute for Biological Cybernetics, Max Planck Society, ou_1497794              

Content

show
hide
Free keywords: -
 Abstract: ‘Smart’ contrast agents (CA) exhibit dynamic and reversible modulation of their relaxivity by specific physiological or biochemical triggers such as changes in pH, Ca2+ concentration or enzymatic activity (1-3). The extracellular concentration of Ca2+ plays important role in physiological and pathological processes in the nervous system. This led to the designing of a chelating system in which relaxivity is influenced as a function of Ca2+ concentration by changing coordination number around the paramagnetic metal ion. We synthesized a novel bifunctional bismacrocycle [Gd-(DO3A-DTPA- DO3A); Fig.] based on DO3A-EA [4,7-Bis-carboxymethyl-10-(2-aminoethyl)-1,4,7,10-tetraazacyclododec-1-yl-acetic acid] coupled to DTPA-bis-anhydride via a flexible alkyl spacer to form the amide linkages. The overall yield of the four step synthesis starting from cyclen was 54. This gadolinium-based agent has two limiting conformational states with different Ca2+ concentrations. It is hypothesized that in the absence of Ca2+, the carboxylates of the DTPA ligand interact with the Gd3+ ions which were held in DO3A, but in the presence of Ca2+, these carboxylates rearrange to chelate Ca2+ thereby allowing water to bind directly to Gd3+. NNNNHNONNOHOOGdOOOOOONNNNOOOOOOGdNOOOONHGd-(DO3A-DTPA-DO3A) Results: MR relaxivity of Gd-(DO3A-DTPA-DO3A) at pH 7.4 in the absence of Ca2+ was found to be r1 = (5.02±0.05) s-1mM-1. In the presence of 1mM Ca2+ r1 was (6.18±0.06) s-1mM-1 and 100mM Ca2+ r1 was (7.69±0.06) s-1mM-1. These data indicate 23 relaxivity enhancement from 0-1mM Ca2+ concentration under physiological conditions thus exhibiting a possibility for use as extracellular calcium sensitive CA.

Details

show
hide
Language(s):
 Dates: 2005-07
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: -
 Identifiers: BibTex Citekey: 3498
DOI: 10.1162/15353500200500210
 Degree: -

Event

show
hide
Title: 4th Annual Meeting of the Society for Molecular Imaging (SMI 2005)
Place of Event: Köln, Germany
Start-/End Date: 2005-09-07 - 2005-09-10

Legal Case

show

Project information

show

Source 1

show
hide
Title: Molecular Imaging
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: -
Pages: - Volume / Issue: 4 (3) Sequence Number: 112 Start / End Page: 240 Identifier: ISSN: 1536-0121